Squid Proxy Server

Install and Configure Squid Proxy Server

Introduction

Squid is an excellent open source web caching proxy package but is requires quite a lot of tuning to achieve the kind of performance seen in commercial proxies. This report present several independently useful ideas for tuning a web caching system

Squid Proxy overview

Squid is a Unix-based proxy server that caches Internet content closer to a requestor than its original point of origin. Squid supports caching of many different kinds of Web objects, including those accessed through HTTP and FTP. Caching frequently requested Web pages, media files, and other content accelerates response time and reduces bandwidth congestion. A Squid proxy server is generally installed on a separate server than the Web server with the original files. Squid works by tracking object use over the network. Squid will initially act as an intermediary, simply passing the client's request on to the server and saving a copy of the requested object. If the same client or multiple clients request the same object before it expires from Squid's cache, Squid can then immediately serve it, accelerating the download and saving bandwidth and Website operators frequently will put a Squid proxy server as a content accelerator, caching frequently viewed content and easing loads on Web servers. Content delivery networks and media companies employ Squid proxy servers and deploy them throughout their networks to improve the experience of viewers requesting programming, particularly for load balancing and handling traffic spikes for popular content. Squid is provided as free, open source software and can be used under the GNU General Public License (GPL) of the Free Software Foundation. Squid was originally designed to run on Unix-based systems but can also be run on Windows machines. Squid was originally an outgrowth of the Harvest Project, an ARPA-funded open source information gathering, and storage tool. "Squid" was the code name used to differentiate the project when development in the new direction was initially begun

Supported Protocols

Squid supports the following incoming protocol request types (when the proxy requests are sent in HTTP format)

HyperText Transfer Protocol (HTTP), which is the specification that the WWW is based on. File Transfer Protocol (FTP) 2
Gopher
Wide Area Information Services (WAIS) (With the appropriate relay server.)
Secure Socket Layer - which is used for secure online transactions.

Inter-Cache and Management Protocols

HTTP, which is used for retrieving copies of objects from other caches.
Internet Cache Protocol (ICP). ICP is used to find out if a specific object is in another cache's store.
Cache Digests. This protocol is used to retrieve an index of objects in another cache's store. When a cache receives a request for an object it does not have, it checks this index to determine which cache does have the object.
Simple Network Management Protocol (SNMP). Common SNMP tools can be used to retrieve information about your cache.
Hyper Text Caching Protocol (HTCP). Though HTCP is not widely implemented, Squid is in the process of incorporating the protocol

Installing Squid Proxy Server

Squid can be installed using the source code or binary package

Installing Squid from source code

Installing Squid from source code is a three step process:

Select the features and operating system-specific settings.
Compile the source code to generate the executables.
Place the generated executables and other required files in their designated locations for Squid to function properly.

Installing Squid from binary

Squid binary packages are available in the software repositories of most operating systems and we can install them by using the package managers provided by the respective operating systems.

Fedora, CentOS or Red Hat

Yum is a popular package manager on RPM-based operating systems. Squid RPM is available in the Fedora, CentOS, and Red Hat repositories. To install Squid, we can simply use the following command: yum install squid

Debian or Ubuntu

We can use apt-get to install Squid on Debian or Ubuntu: apt-get install squid3

FreeBSD

Squid is available in the FreeBSD ports collection. The following command can be used to install Squid on FreeBSD: pkg_add -r squid31 For more information on package management in FreeBSD, please go to http://www.freebsd.org/doc/handbook/packages-using.html.

OpenBSD or NetBSD

Installing Squid on OpenBSD or NetBSD is similar to installing it on FreeBSD and can be performed using the following command: pkd_add squid31 To learn more about the package management system in OpenBSD and NetBSD, please refer to http://www.openbsd.org/ports.html#Get and http://www.netbsd.org/docs/pkgsrc/using.html#installing-binary-packages respectively.

Dragonfly BSD

To install Squid on Dragonfly BSD, we can use the following command: pkg_radd squid31 For more information on installing binary packages on Dragonfly BSD, please visit http://www.dragonflybsd.org/docs/newhandbook/pkgsrc/.

Gentoo

We can install Squid on Gentoo Linux using emerge, as shown next: emerge =squid-3.1*

Arch Linux

To install Squid on Arch Linux, we can use the package manager pacman, as shown in the following command: pacman -S squid For more information on pacman, please visit https://wiki.archlinux.org/index.php/Pacman Next chapter

onward all configuration command based Debian or Ubuntu because we are used Debian for Operating system

Basic Configuration in Squid proxy

The default configuration file is probably right for 90% of installations - once you have Squid running, you should change the configuration file one option at a time. Squid configuration file locate on /etc/squid/squid.conf

Setting Squid’s HTTP port

The first option in the squid.conf file sets the HTTP port(s) that Squid will listen to for incoming requests

http_port 3128

Store cache data

The cache_dir operator in the squid.conf file is used to define cache directory, its path, type and size
cache_dir Type Directory-Name Mbytes Level1 Level2 [options]
Eg-:cache_dir ufs /usr/local/squid/var/cache/ 100 16 256

Access Control Lists and Access Control Operators

This is used for filtering based on the acl matchings. If none of the "access" lines cause a match, the default is the opposite of the last line in the list. If the last line was denied, then the default is allowed. Conversely, if the last line is allowed, the default will be denied. For these reasons, it is a good idea to have a "deny all" or "allow all" entry at the end of your access lists to avoid potential confusion

http_access deny !Safe_ports

http_access deny CONNECT !SSL_ports

http_access allow localhost manager

http_access deny manager

http_access allow localnet

http_access allow localhost

http_access allow all

Set Host Name

unique_hostname Anusha

visible_hostname Anusha

Browser Configuration

Squid is the server half of a client-server relationship, after that server configuration we must configure the client. Actually, client configuration mean our web browser configuration. Figure 5.1 show how to configure web browser

Anusha Chathuranga

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